Pain killed Kakashi during his attack on the
With the dual Mangekyo Sharingan, Kakashi would be able to overwhelm even Pain. Between the space-time ninjutsu that allows, the full Susano'o at Kakashi's disposal, and the Copy Ninja's notorious intellect and strategy ability, Kakashi would likely be able to conquer Pain with relative ease.
Double Mangekyou Sharingan Kakashi would beat Pain without any issue. Kakashi would only need to use his Susanoo to fly out of range and then bombard them with his Kamui shuriken.
Kakashi wins with difficulties. He have Perfect Susanoo and Kamui Shurikens. He is also faster than Nagato and have Six Paths Chakra and both Kamui variations.
Sasuke is yet another strong character in the Naruto series who eventually surpassed Kakashi. Sasuke was so strong that he was able to perform jutsus like Indra's Arrow which has similar, if not the same destructive capabilities compared to Naruto's Six Paths: Ultra Big Ball Rasenshuriken.
Kakashi's own double Mangekyo Sharingan power is far superior to Guy's eight gates. Even though Guy almost touches the speed of light, Kakashi's Kamui is instantaneous. He's fast enough to blitz even Kaguya Otsutsuki, and as such, Might Guy stands no chance.
The truth is, compared to other Jonin, Kakashi is not actually low on chakra reserves. In fact, he has a pretty high capability. The weakness comes when battling the best villains in the series. Kakashi does not match up to the strongest and most gifted of legendary shinobi.
Kakashi does battle Itachi early in the series. Itachi ends up trapping him in a genjutsu and draining Kakashi. The contest basically ends up in a loss for Kakashi, but that is somewhat debatable. Still, Itachi shows more control over his Sharingan and the ability to match Kakashi.
Kakashi is one of the most powerful and skilled (non-Six paths enhanced) ninja in the entire series by the end of shippuden. His wide arsenal of Jutsu paired with his brilliant tactical mind makes him a formidable opponent to say the least.
Jiraiya is far more experienced than kakashi and he also has powerful jutsus. Jiraiya was the fourth hokage, Namikaze Minato's sensei who was also kakashi's sensei so it's safe to say jiraiya can beat kakashi.
Final thoughts. There is no doubt that Kakashi is quite strong despite the loss of Sharingan. He is by no means weak and can hold his ground against tough opponents. Whether it be his ninjutsu, taijutsu, or shuriken jutsu, Kakashi has mastered them all.
I at least think it's because Kakashi is such a powerful Shinobi that Pain just “felt the need” to acknowledge him. Kakashi survived the Shinobi world for so long with that Sharingan from a clan thought nearly extinct so people will take notice on him because of his “uniqueness”.
Itachi was able to fight against Naruto Uzumaki in his Nine-Tails Chakra Mode, something that Pain could never do. He was also able to incapacitate Nagato Uzumaki, and it is quite easy to see that he could definitely have taken on and defeated Pain in combat.
Furthermore, Sasuke was able to obtain the Rinnegan Eye and the Eternal Mangekyo, giving him another edge against Kakashi. While Kakashi is a brilliant tactician and generally a powerful warrior, he just wouldn't be able to measure up to Sasuke Uchiha as he is now.
This would be an interesting fight but gaara is no match for kakashi. The son of white fang of the leaf kakashi hatake (the copy ninja) will win the fight no matter what. The person above was chosen to be the sixth hokage of konoha for his exceptional capabilities. He is feared in all five great nation's.
As has already been established, the weakest Hokage of Konohagakure is between Kakashi Hatake and Tsunade Senju. In fact, both Kakashi and Tsunade are quite close to each other in terms of strength in Naruto. However, their fighting style differs a lot from each other.
Abilities. Like his son, Sakumo was a gifted shinobi praised for his talents in the ninja arts even by the likes of Minato Namikaze, the Fourth Hokage. In battle, Sakumo was a truly powerful shinobi, his prowess surpassing that of the Sannin.
Minato has the Kurama form but still he can't beat Kakashi with the Susanoo and kamui. Minato wins because due to Kakashi average chakra reserves he can't hokd out PS for too long. So he'll run out too quickly.
6 Eight Inner Gates
While Kakashi isn't specifically skilled in taijutsu like Guy, he can still access the Eight Inner Gates.
In the very much parodic spin-off series Rock Lee & His Ninja Pals, it's stated that Kakashi constantly wears a mask to hide the nosebleeds he suffers while reading his favorite (adult) book series.
Kakashi, as his former friend and sensei, cnan defeat Obito in a fight. The two of them have clashed, and while Obito was able to injure Kakashi, it was Kakashi who dealt a more decisive blow to Obito and would have killed him had he not gone to help his allies in battle.
In the Boruto era, Kakashi is certainly weaker than he was in Naruto since he lost his Sharingan, and in the process, a big chunk of his powers.